An unprecedented solvent-controlled, regio-switchable Knorr-type reaction for the synthesis of pyrazoles has been realized in the cyclocondensation of β-aminoenones with hydrazides. Single regioisomer of 3- or 5-arylaminopyrazole can be obtained simply by changing the reaction solvent. Using hydrazine hydrate, only 3-arylaminopyrazoles were produced.
在δ-
氨基
烯酮与酰
肼的环缩合反应中,实现了一种前所未有的溶剂控制、可进行区域切换的克诺尔型
吡唑合成反应。只需改变反应溶剂,就能得到 3- 或 5- 芳基
氨基
吡唑的单一区域异构体。使用
水合
肼只能生成 3-芳基
氨基
吡唑。